When accelerating in my car I get a rattling noise right at about 4200-4400RPM's then it goes away and does not happen anywhere else in the RPM range, this noise happens in every gear. The rocket scientist at the infiniti dealership think its from my aftermarket exhaust lol. Too bad it was happening before that was installed. It seems like it started happening right after my KJR pulley install, they checked the pulley out and everything was ok but the problem still remains. I wonder if those jackasses didnt tighten a bolt down all the way somewhere like they forgot to do on the bottom of my stillen intake. Any ideas? Maybe the engine vibrates alot at that specific RPM range causing some loose bolt to rattle ?

 

Yeah, grab a pistol, stick it up the dealers a$$, and rattle it. Tell him thats how you feel when the car rattles on you.

 

[Mechee]The pulley's added 0.000012362hp caused your engine to reach super hyper-fluxation, as provided by SHF=(e^2/9)*ln(4) - 1[/mechee]

 

tell tehn you want to go on a road test with their shop foreman. and make the car rattle and he might be able to figure it out..

 

[99atlantic] I dunt belief in them sciences stuff. Them don't make no sense. Praise da lord fer lightened pullies and grounding wires.[/99atlantic]

You've been smitten for installing that pulley. It's probably the 25% increase in acceleration causing something to hit in the engine bay.

 

Check your intake. It could be rubbing against the ac line causing the vibrating noise during hard acceleration.

 

How did they check the pulley? Hopefully no one dropped it. Maybe it has a dig or bent a bit and you're getting a bit of vibrations. As it vibrates through the RPM's it emits a frequency and at a certain point it will be profound. I hope you get what I'm trying to say. Maybe MechEE can help me out here. No I'm not trying to an A**hole MechEE. Hope it helps

 

Dat der's right..............now where's ma sister, I need to have secks with her and breed somemo' younguns

 

Where does it sound like it is coming from?

You said it happens at the same RPM, in every gear. Does it happen in neutral?

 

No sir , not in neutral (atleast I cant hear it when I rev). It ONLY happens when I floor it and wind through the RPM range. It kind of sounds like coins rattling for a second, I guess the only real fix would be to install the old pulley and see if the sound is still there. I asked the tech and he said if it was the pulley causing the noise it would be more of a vibrating sound and not just happen at that specific RPM.

 

if it was the pulley i'd agree that it wouldn't just happen at a certain point

what this reminds me of is exhaust issues - some piping is either loose or touching against something under the car (brace, heatshield, floorpan, etc...)

I'd make triply sure that ALL parts of the exhaust clear everything.

 

OMFG that was funny...

 

It was happening before the HKS install, right after the car left the dealership after pulley install

 

Please don't breed!

Does it resonate when reving the car through that RPM range in neutral, or only under load?